Vitamin supplements: good or bad?

Written by Colin Brennan, medical journalist

In 2006 Britons spent £220 million on vitamin and mineral supplements, according to the Food Standards Agency (FSA). What's more, it found 43 per cent of UK adults had taken vitamin or mineral supplements in the past 12 months with usage highest among the 50-65 age group.

While the most popular supplements were cod liver oil and multivitamins, it's sales of 'mega-dose' vitamin and mineral products that are growing fastest, with some manufacturers reporting an increase of more than 20 per cent in the last three years.

Undeterred by the occasional warning that it is possible to damage the body by overdosing at the breakfast table, it seems there is a determination to seek the elixir of life at a cost of up to £30 a time.

A shortcut to health

That we need vitamins is not in dispute. Vitamins are a small group of substances that are essential in tiny quantities for growth and development. Most of them cannot be manufactured by the body and must come from our diet.

But some people think that if you take vitamin pills by the handful, you don’t have to bother watching what you eat. It is easy to see the attraction of an approach whereby you can exist on junk food, have a terrible lifestyle and still be 'healthy'.

Other people take a less extreme view and try their best to follow the prevailing health advice. They recognise that they will fall short of the ideal and take vitamins as a kind of insurance policy.

Doctors, too, thought this was a good idea. After all, in laboratory tests vitamins E and C had a powerful effect on the 'free radicals' that are linked to all sorts of medical problems from cancer to heart disease.

Many studies have since shown that vitamins from supplements do not act on the body in the same way as vitamins from foods.

Apples and pills

Take apples: they are a rich source of vitamin C, which builds up the immune system. But when researchers at Cornell University in New York compared the effects of apples and vitamin C tablets, the results were quite startling.

The apples contained many other naturally occurring chemicals in addition to vitamin C, including antioxidants called flavanoids and polyphenols that are thought to protect against cancer.

This meant that eating a small apple (100g) gave an antioxidant effect equivalent to taking 1500mg of vitamin C – and you'd have to take a mega-dose supplement to achieve that.

One of the study’s authors, Professor Chong Yong Lee, said: 'Some of the chemicals we found in apples are known to be anti-allergenic, some are anti-carcinogenic, anti-inflammatory and anti-viral. Now I have a reason to say an apple a day keeps the doctor away.'

In contrast, a 2004 Cochrane review of studies found there was not enough evidence that 2000mg vitamin C supplements prevented colds in the general population. More recently, the US Women's Health Study found a link between vitamin C supplements and an increased risk of hardening arteries in some people with diabetes.

A good diet is best

Calcium

Calcium is vital for those in their teens or early 20s to protect against osteoporosis (bone thinning) in later life.

Supplements can't make up for a deficiency of calcium in your youth.

Dietitians, nutritionists and other experts are all agreed that apart from small groups of people in special medical circumstances, most of us don't need to take vitamins or food supplements. We can get what we need from a balanced diet.

Sarah Schenker, a dietitian and spokesperson for the British Nutrition Foundation, told NetDoctor: ‘Although some groups of the population do require vitamins and supplements, a healthy diet is the best way to obtain the vitamins we need.

‘One of the most important pieces of advice we can give is to increase your fruit and vegetable consumption. These are the foods that are nutrient rich, vitamin rich and mineral rich. Current advice is to try to have five portions per day. This is quite a tall order and many people don’t even have half the recommended quantity.

‘It has been discovered that these foods contain far more than the classic vitamins and minerals we all know about. They contain many other plant substances, known as phytochemicals, which can’t be put in a bottle or made into a pill.’

It's the food, not the pill, that is potent.

When to pop the pills

Elderly people

Elderly people do not automatically need to take supplements.

The following reasons may mean supplements are necessary:

• problems eating due to loss of appetite
• dental difficulties
• problems with swallowing or digestion
• being housebound.

The following groups of people may need to take vitamin supplements.

• Women who are planning to get pregnant or have just become pregnant should take a daily supplement of 400mcg folic acid to help prevent spina bifida.
• Women who cover up in black robes and have only a limited exposure to sunlight may lack vitamin D, which could be taken in supplement form. This could also apply to housebound people.
• Vegans who never eat meat or dairy products may need to take vitamin B12 in tablet form.
• People who are malnourished: this may be because they have been ill, or have difficulty eating or swallowing for medical reasons. It can include people who have been on a weight-loss diet. Slimmers should think of eating more fruit and vegetables to avoid possible vitamin deficiencies.
• People who are doing intense training for sport.

For nutrition and training purposes, you only need to take the most basic and inexpensive multivitamin as a precaution.

Concentrating on single vitamins or areas of nutrition can be a mistake, according to Sarah Schenker. Overall health is best promoted through a balanced diet.

Possible dangers

A further reason to avoid mega doses of vitamins is that they can have toxic effects. We do need vitamins, but more is not necessarily better.

This is particularly true with the fat-soluble vitamins that will be stored in the liver, like vitamin A. They can eventually reach toxic levels and cause liver damage.

Even the water-soluble vitamin C can cause diarrhoea at levels of 2000mg a day, which is lower than the amount some people take in the hope of staving off colds.

A question of need

Taking vitamins and food supplements is neither good nor bad, but unnecessary for most of us. There is a lot to be said for saving the money and splashing out once in a while on a nutritious and delicious well-balanced meal at a ritzy restaurant instead.